Friday, July 26, 2019

During the hazy, lazy days of summer, most folks are thinking of relaxing on the beach or by the pool.

Not us.

At Latem Industries, our summer focuses on removing rust that has unexpectedly occurred on our customer’s parts and equipment.

Why? When the atmospheric conditions are right, rust can form on unprotected metal from the humidity alone. Humidity-based corrosion is something that keeps us busy all summer long.

Unfortunately, many of our customers aren’t even aware of humidity-based corrosion until the rust has already occurred. Don’t let it happen to you! Here’s what you should know about preventing and removing rust and corrosion caused by humidity.

How Humidity Affects the Rate of Corrosion

How does humidity cause corrosion? That’s an important question in the mass metal finishing and parts coating industries. To prevent and manage humidity-based corrosion, we have to first understand how it works.

Metal corrodes at a much greater rate under humid conditions. This happens because the moisture-saturated air reacts with oxygen and electrons on the surface of the metal. The longer metal components are exposed to humid air, the faster they will generally corrode.

This type of atmospheric corrosion can occur when the amount of moisture in the air reaches critical humidity, which is the point at which water no longer evaporates or gets absorbed from the atmosphere. In most conditions, this happens at 80% relative humidity (RH).

But it’s not simply the humidity that causes corrosion; it is the change in temperature along with a significant increase in humidity that causes moisture to form on parts. There are two ways this can happen.

Second, when a surface cools below the temperature of the surrounding air, moisture will form on the surface as condensation. This is likely to happen in most manufacturing facilities as the temperature within the facility cools overnight. Later, when the sun comes up and the temperature rises again, humidity causes moisture to condense on cool, metal surfaces.

The higher the relative humidity, the smaller the temperature difference needed for condensation to form...which sets the stage for corrosion to occur.

How to Prevent Humidity from Creating Corrosion

In a perfect world, we would keep all our precious equipment in a climate-controlled facility that is never affected by the humidity. Of course, most of the metal parts we process aren’t meant to stay in a bubble, so we have to find other ways to protect them.

The simplest and most cost-effective way to protect parts from humidity-based corrosion is to seal them against moisture. This can be accomplished by placing large quantities of parts in Vapor Corrosion Inhibitor packaging, which slowly releases an anti-corrosion compound to protect exposed metal surfaces from corrosion.

How to Remove Humidity-Based Rust

What if the corrosion has already occurred? There is a significant expense and loss of revenue when you are forced to scrap processed parts due to rust.

Fortunately, scrapping parts is seldom the only solution! It’s possible to clean rust from almost any manufactured metal part quickly and cost-effectively, then treat them with a rust inhibitor to prevent it from happening again.

The best process for removing rust from mass quantities of parts usually depends on the extent of corrosion and the geometry of the part. Latem has the capacity to clean away rust from millions of parts daily. Whether the part is the size of a thimble or as large a sheet of stainless steel, we have the best processes available to quickly and cost-effectively remove rust.

Friday, June 28, 2019

Shot peening is a time-tested method of enhancing and strengthening the surface of steel. It is employed as a practical and cost-effective way to extend the lifespan and performance of metal parts in numerous industries.

By introducing residual stress on the surface in a controlled manner, shot peening creates a compressive pressure layer that is more resistant to cracking, fatigue, and oxidation.

How Shot Peening Works

Shot peening entails blasting the part with shot (small beads of metallic, glass or ceramic particles) with sufficient force to create tiny indentations in its surface. Each shot acts as a tiny ball-peen hammer loaded with enough kinetic energy to cause plastic deformation - meaning the metal bends slightly on impact but doesn’t chip or fracture.

When this happens, an area of stress is created on the surface of the part. The material directly beneath the indentation, meanwhile, resists and becomes compressed. Each indentation makes the surface of the material stronger and more resistant to cracking.

This process repeats thousands of times during shot peening, gradually building up a strengthened stress layer that encases the entire component!

Shot Peening or Shot Blasting?

Shot peening is similar to shot blasting...but differs slightly in process and end result.

Both operate by the mechanism of plasticity, changing the surface of the part while minimizing the amount of material removed in the process. However, shot blasting is most often used to clean and prepare components prior to coating. Shot peening, on the other hand, is used to make components stronger.

How Shot Peening is Applied

Shot peening is used to compensate for tensile stresses that occur during machining. Parts that have been through processes like grinding, milling, bending and heat treatment can often benefit from shot peening.

Improved oxidation resistance of nickel-based alloys: These alloys have wide applications in the aerospace, marine and chemical industries.

Parts that are commonly shot peened include:

Crankshafts

Gear wheels

Connecting rods

Automotive gear parts

Coil springs

Turbine blade

Airframe components

Suspension springs

How to Measure Shot Peening Results

Shot peening results are measured using an Almen Strip test.

A flat test strip is placed in the shot chamber to absorb the intensity of the blast, causing it to deform into an arc shape. The height of the arc directly relates to the intensity of the peening blast and the resulting compressive stress.

Monday, January 21, 2019

Steel surfaces can sometimes exhibit residual mill scale as a side effect of the production process. Though not harmful in and of itself, the presence of scale is detrimental in conditions where corrosion is likely to occur, and it must be removed before a workpiece can be given a protective coating.

This post discusses the role of mill scale in the steel production and coating process, including the fastest way to remove mill scale from surfaces.

Identifying Mill Scale

Mill scale (often known simply as ‘scale’) refers to the thin, flaky texture that forms on the outer surface of hot-rolled iron oxides and metals. It is a by-product of manufacturing hot-rolled metal plates and sheets, occurring as the surface oxidizes during the heating, conditioning and hot rolling processes.

Scale has a distinctive blue-grey colour and a flaky or powdery consistency. It is not a continuous layer, but rather a thin, uneven coat (1mm thickness or less) of mixed iron oxides that chips easily on contact.

Unlike rust, which forms over a long period of exposure to oxygen and moisture, scale forms on all steel and iron products that are hot rolled. The only way to prevent its appearance would be to manufacture them in an inert atmosphere.

Mill scale is not in itself harmful to the workpiece. In fact, in the short term, a layer of scale helps to protect the metal’s surface from corrosion and other negative atmospheric effects. The problem begins when the mill scale breaks – which, given its brittleness, is practicably inevitable during handling, storage or transportation.

Why Mill Scale Must Be Removed

Scale is very fragile, and the moment it cracks, it turns from a protective barrier to a detriment.

Mill scale is less reactive than the steel surface it covers, acting as a cathode to the more reactive material underneath. Once the scale coating breaks (which occurs easily) and moisture comes through, the presence of the scale iron oxide accelerates the corrosion process at the breakage point.

The presence of mill scale is also a hindrance to applying paint or powder coating, which adheres poorly to scale. Left in place, the scale will eventually chip and break the coating’s surface, allowing moisture to penetrate.

It is wasteful to apply a protective coating over a workpiece covered with mill scale. For this reason, scale removal is an indispensable step in the pre-coating process.

Removing Mill Scale from Iron or Stainless Steel

To achieve a smooth, durable coating, mill scale must be removed from an iron or steel workpiece before application. This is true for powder coatings, paints and other finishing techniques meant to protect the surface from corrosion.

Shot Blasting, a method used to clean, strengthen and polish metal, is a fast and cost-effective way to remove mill scale. This service is normally carried out to prepare the surface of steel before applying any coating. Having the steel prepared by shot blasting is generally considered to be the most important factor affecting any corrosion protection system or coating.

Thursday, November 15, 2018

Imagine processing and shipping thousands of parts to your customer – only to discover your shipment was rejected due to rust.

Rust or corrosion is a significant issue in manufacturing facilities large and small, impacting resources and increasing operating costs. Rust is difficult to prevent and nearly impossible to anticipate on manufactured parts.

When rust occurs, leading manufacturers look to Latem Industries for metal finishing solutions. Here’s how we can help.

So, What Exactly Is Rust?

Rusting is the common term for corrosion of iron and its alloys, such as steel.

Surface rust can be spotted or flaky and does not protect the underlying iron, which enables the oxide to grow. With enough time, oxygen and moisture will eventually convert an iron part entirely to rust and disintegrate it.

How Latem Solves the Problem

Latem Industries uses various processes to remove rust or corrosion from processed parts:

The best process for removing rust from mass quantities of parts is often determined by the extent of the corrosion and the geometry of the part.

For minor rust problems around your home or workshop, you can try using this simple home solution: salt + lime. Sprinkle a little bit of salt on the rust, then squeeze the lime over the salt until it is soaking. Let the mixture sit for 2-3 hours and then remove the rust with the lime rind. This can also be done with a lemon, but we like the salt and lime a little more because they double as margarita ingredients.

Mass Metal Finishing Solutions for Rust or Corrosion

Latem (metal spelled backwards) has the capacity to clean away rust from millions of parts daily. Whether the part is the size of a thimble or as large as a sheet of steel, we have the best processes available to quickly and cost-effectively remove rust.

Thursday, September 27, 2018

The team at Latem Industries is proud to announce our recognition as an ISO 9001:2015 certified metal finisher. We’ve worked hard to implement processes and produce results that meet these rigorous quality standards.

ISO 9001:2015 Certification: What Does it Mean?

These standards apply across all industries, products and services, including metal finishing. The ISO is recognized worldwide and endorsed by both the Standards Council of Canada (SCC) and the American National Standards Institute (ANSI).

ISO 9001:2015 is the latest revision to these standards. ISO 9001:2015 provides a clear roadmap to guide companies like Latem Industries in meeting (and surpassing) customer expectations and regulatory requirements.

Being ISO 9001:2015 certified is something that matters both to us and our customers. Internally, it demonstrates our commitment to the quality and consistency our customers expect. That means delivering exceptional metal finishing services and customer service that goes above and beyond what our customers expect.

When you see that a company has earned ISO 9001:2015 certification, you can trust that their promises are backed by a universal quality management process.

Latem’s ISO 9001:2015 Certificate

This certificate demonstrates that Latem Industries’ Quality Management System and processes passed an independent audit by an accredited certification body. Our audit was conducted by The Registrar Company, a trusted certification body accredited by the ANSI-ANQ National Accreditation Board (ANAB).

ISO 9001:2008 vs. ISO 9001:2015

If you’re already familiar with the previous standards set in 2008, you’ll find few changes in the ISO’s current criteria. What has changed is:

Thursday, February 22, 2018

When given the proper protective coating, metal parts can function more effectively and last much longer. However, before the coating process can start, an important preliminary procedure is necessary. As the effectiveness of the coating depends greatly on the quality of the surface, not performing pre-treatment means the surface is in less-than-optimal shape. That leaves the metal open to corrosion, adhesion, flash rusting, weld pullaway, and impact resistance issues, the very problems that proper coating prevents. Here are five common pre-treatment steps to prepare metal parts for coating.

Disassembly

Many different types of parts pass through our facility every year. Some are single pieces, while others consist of several different components. In most cases, the latter requires disassembly, because the coating process will not benefit each part (or could even damage some).

Cleaning

Just as you would not paint a dirty surface in your home, some parts need to undergo cleaning before coating begins. Pressure washing and ultrasonic cleaners are very effective methods. Extra care is necessary when using cleaning solutions as some metals are especially sensitive. Exposure to the wrong chemicals can create damage that is not visible to the naked eye, but serious enough to compromise both the coating process and the life/utility of the part.

Stripping

Even after cleaning, it may be necessary to perform this additional step to ensure an entirely clean surface. Some parts are not new and already have remnants of a previous coating still on them. It is necessary to strip any remaining bits of paint, plastic or another form of finish before applying the new coating. Failure to do so means the new layer will not properly adhere.

Outgassing

The idea is to make sure you reach bare metal before the coating process begins; outgassing is another way to achieve this. It is not obligatory for all parts, but ones made of cast aluminum or cast iron tend to be more porous. That can allow oil and other contaminants to get inside. Applying the coat with those materials still present undermines the part’s ability to perform and last the expected lifespan.

Outgassing involves baking the part in an oven at a temperature that causes the oils to burn off. There is often some smoke generated as a result.

Shot Blasting and Shot Peening

Shot blasting involves the high-speed projection of steel shot at the material chosen for coating. The shot permeates the surface, and this dislodges the foreign matter. The blasting media used varies depending on the type of metal being treated and the desired finish.

Shot peening will also clean the surface of parts scheduled for coating. With this process, the shot performs the same function as a ball-peen hammer. Both of these processes have the added benefit of strengthening the metal, thus reducing the likelihood of corrosion, cracking, and stress failure.

Tuesday, January 23, 2018

Shot blasting and shot peening are common processes in the manufacturing world. If the industry uses metal parts, chances are it relies on shot blasting and peening to make things work.

What is the difference between shot blasting and shot peening? While similar, the two are distinct processes with different goals. Read on to learn what sets them apart.

What is Shot Blasting?

Manufactured metal parts aren't ready for use right out of the mould. They often need a coat of paint, powder coating, or welding work. But before this can happen, the surface of the metal part must be clean.

Shot blasting prepares metal parts for further processing like painting or powder coating. This step is necessary to ensure the coat adheres properly to the part. Shot blasting can clean off contaminants like dirt or oil, remove metal oxides like rust or mill scale, or deburr the surface to make it smooth.

How Shot Blasting Works

Shot blasting involves shooting a high-pressure stream of abrasive material (also known as shots or blasting media) against the surface of a metal part. Depending on the application, the shots may be propelled by a pressured fluid (like compressed air) or a centrifugal wheel (known as wheel blasting).

The shape, size and density of the shots will determine the final results. Types of metal abrasives used in shot blasting include steel grit, copper shots, and aluminum pellets. Other methods of shot blasting use silica sand, glass beads, synthetic materials like sodium bicarbonate (baking soda), and even agricultural materials like crushed kernels.

What is Shot Peening?

To explain shot peening, one must first understand the general notion of peening. It is possible to strengthen the material properties of metal by applying stress to its surface. This expands the surface of the metal, creating a layer of compressive stress and relieving tensile stress in the piece.

Working the surface of metal to increase its strength is called peening. The traditional method involves striking the metal with a ball-peen hammer, which is inefficient in a large-scale manufacturing setting. Today, most industries employ mechanical shot peening instead.

How Shot Peening Works

Shot peening and shot blasting both involve shooting a stream of material against the part's surface. The biggest difference between shot blasting and shot peening is the end result. Shot blasting uses abrasives to clean or smooth the surface to prepare it for processing; shot peening uses the plasticity of metal to prolong the life of the part.

In shot peening, each shot acts as a ball-peen hammer. The process makes the surface of the metal part stronger and more resistant to cracks, fatigue, and corrosion. Manufacturers can also use shot peening to give the piece a textured surface.

Like with shot blasting, the choice of shot depends on the application. Shot peening usually involves steel, ceramic, or glass shots. The material is reusable, making it an efficient and cost-effective process for strengthening metal parts.

Shot blasting and shot peening are both critical steps in the metal manufacturing process. Often, a part will undergo both before it’s ready for use.